This invention relates to the storage of wheeled trailer frames, or chassis, of the type used to haul cargo containers. More specifically it relates to the storage of such trailer frames in a vertically-stacked relationship, such that the ground-engaging wheels of the lowest trailer frame in the stack may turn freely to permit towing of the stack.
Wheeled trailer frames, also referred to as chassis, often are stored at shipping or rail-loading sites in large quantities. Due to their size they occupy a large amount of space if merely parked in horizontally-disposed condition adjacent each other on the ground.
Efforts have been made to save ground space by storing such chassis in tilted-up arrangement in support frames. Other attempts have been made to save space by stacking the trailer frames, or chassis, one atop the other.
In the tilted-up, or vertical storage, specialized storage frames and tilting equipment are required. In prior stacking arrangements one trailer frame is stacked atop the other with the wheels of each chassis interlocking, or engaging, the wheels of the chassis therebelow. With the wheels thus locked the stack may not be repositioned easily by tractor towing.
In the past efforts have been made to overcome this wheel-lock problem by providing rather complex support frames mounted on the lower-most frame to support overlying chassis. In other instances attempts have been made to overcome this problem by inverting the chassis laid atop the lower-most ground engaging chassis, such that the inverted chassis wheels do not engage and interlock with the wheels on the lowermost chassis. Although this has allowed the wheels of the ground-engaging chassis to rotate to permit tractor-towed moving of the stack, it has required specialized equipment to invert the overlying chassis and results in added work time. Further, chassis stacked in this fashion may not be safely transportable because the inverted chassis may slide on the ground engaging rolling chassis.